(E)-N′-(3,4-Dihydroxybenzylidene)-2,4-dimethylbenzohydrazide monohydrate

In the title compound, C16H16N2O3·H2O, the dihedral angle between the benzene rings is 30.27 (7)°. In the crystal, the components are linked by N—H⋯O, O—H⋯O and C—H⋯O interactions into a three-dimensional network.

In the title compound, C 16 H 16 N 2 O 3 ÁH 2 O, the dihedral angle between the benzene rings is 30.27 (7) . In the crystal, the components are linked by N-HÁ Á ÁO, O-HÁ Á ÁO and C-HÁ Á ÁO interactions into a three-dimensional network.
Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL, PARST (Nardelli, 1995) and PLATON (Spek, 2009  Structurally diverse range of benzohydrazides have been extensively studied in order to explore the structural features that may be responsible for different biological activities (Musharraf et al., 2012;Khan et al., 2012). The title compound is yet another benzohydrazide monohydrate, obtained as a part of our ongoing research that has been studied by X-ray crystallographic method and reported in this article.

Experimental
The title compound was synthesized by reacting (0.328 g, 2 mmol) 2,4-dimethylbenzohydrazide and (0.276 g, 2 mmol) 3,4-dihydroxybenzaldehyde as starting meterial under the same conditions and solvents as described previously for the synthesis of benzohydrazides . The title compound was recrystalized by dissolving in methanol to obtain colorless needles (0.499 g, 88% yield). All chemicals were purchased by Sigma Aldrich Germany.

Refinement
H atoms on methyl and benzene ring were positioned geometrically with C-H = 0.96 and 0.93 Å, respectively and constrained to ride on their parent atoms with U iso (H) = 1.2U eq (benzene) or 1.5U eq (methyl). The H atoms on oxygen and nitrogen were located in difference Fourier map and refined isotropically. A rotating group model was applied to the methyl groups.

Figure 2
The crystal packing of the title compound. Only hydrogen atoms involved in hydrogen bonding are shown.

Special details
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.